1. Field of the Invention
This invention relates to a magneto-optical recording method suitable for high-speed recording of magneto-optical recording media of the magnetic field modulation mode, typical mini-discs (often abbreviated as MID) and a method for making an information-carrying magneto-optical recording medium.
2. Prior Art
Systems for converting audio and video information into digital signals and recording them in rewritable media as typified by magneto-optical discs are utilized in audio and video applications mainly for consumer use. There is also a tendency that computer software contains an increasing amount of information and it is considered to utilize high capacity media as means for storing and transferring such a vast amount of information. Information must be recorded in an unrecorded media at a high speed before such attempts can be successful in practice. However, many disc media have recording tracks previously inscribed at the shipment from the factory and must obey various restrictions associated with the principle of recording and reading operation. They cannot be recorded by a simple process like magnetic transfer as in the case of magnetic tape and optical transfer. There is no other way than copying information in such a disc on a real time basis, undesirably taking a long time.
Especially for recording in the magnetic field modulation mode, no substantial saving of recording time is expectable since the electronic circuit imposes some restrictions on the recording linear velocity.
Mini-discs (MD) are one class of magnetic field modulation mode recording media. With respect to audio mini-discs, for example, consumers have a demand that in a rental shop or some place where a number of musical tunes are available from gramophonic records, compact discs, and other sources, the consumer carries his or her own mini-disc with, pays a fee to the shop, chooses favorite tunes, and dubs them in the mini-disc to make a private special disc. In such a situation, it is desirable to complete recording within a short time. The recording in the magnetic field modulation mode, however, has system restrictions as mentioned above and does not permit high speed recording above a certain linear velocity because increasing the recording linear velocity above the limit results in outputs with low C/N.
There is a desire to have a method capable of high speed recording without raising such problems.